Synthesis of some thiazolyl and thiadiazolyl derivatives of substituted furan and pyrrole

摘要

Four series of substituted furan and pyrrole have been synthesized. The first series was prepared by cyclization of the key intermediates ethyl 5-[(4-substituted thiosemicarbazido)methyl]-2-methylfuran-3-carboxylates 2a-2d and 1-[(4-acetyl-5-methyl-1H-pyrrol-2-yl)methylene]-4-substituted thiosemicarbazides 8a-8d with chloroacetic acid or (ethyl bromoacetate) to afford the corresponding 4-oxo-3-substituted thiazolidin-2-ylidene 3a-3d or 3-substituted thiazolidin-4-one 9a-9d. On the other hand, heating of the intermediates 2a-2d or 8a-8d with acetic anhydride afforded the corresponding (N-substituted acetylamino)-2,3-dihydro-[1,3,4]thiadiazol-2-yl derivatives 4a-4d and [1,3,4]thiadiazol-2-yl-N-substituted acetamide 10a-10d respectively, while cyclization with p-bromophenacyl bromide gave rise to the corresponding 3-substituted thiazol-2-yl-ylidene 5a-5d and 11a-11d respectively. Furthermore, 4-oxo-3-substituted thioureido-thiazolidin-2-yl 6a-6d or 4-oxo-thiazolidin-3-yl-3-substituted thiourea 12a-12d were obtained by reaction of the intermediates 2a-2d or 8a-8d with thioglycolic acid. Some of the synthesized compounds showed promising antimicrobial activities.